1. Field of the Invention
The present invention relates to a rolling mill drive with joint spindles arranged axially slidably between pinions and work rolls. A joint of each spindle is releasably connected to the neck of at least one roll, particularly of the work roll.
2. Description of the Related Art
In conventional rolling mill stands, the work rolls between which the material to be rolled is worked, for example, a metal strip to be cold-rolled, are driven by drive spindles which are connected to the necks of the work rolls. The drive spindles are connected to driving pinions. The pinions are driven by suitable drive motors with transmissions being arranged between the pinions and the drive motors. At the connections to the work rolls and the pinions, the drive spindles have joints, usually universal joints, for compensating angular displacements caused by varying thicknesses of the strip being rolled.
Since in normal rolling operation, the work rolls must meet high requirements and must be frequently exchanged because of the occurring wear and because of necessary adjustments to the respective rolling program, special structural provisions are made for separating the work rolls and spindles from each other. In known separating devices, the exchange of the rolls including the removal of the necks, of the sliding pieces and the pulling-off of the spindle are very cumbersome and require substantial time and operations.
U.S. Pat. No. 3,670,587 discloses a vertical rolling mill in which the rolls are exchanged by pulling two rolls apart from each other and then moving the rolls downwardly and pulling the rolls with the necks thereof out of the couplings of the drive units. However, this requires expensive and complicated arrangements for displacing and axially moving the work rolls. If the couplings of the drive units are not fixed in their position after the necks have been pulled out, the subsequent insertion of the necks of the new rolls into the coupling is very difficult.
German Offenlegungsschrift 27 33 988 discloses a drive arrangement for vertical rolling mill rolls. The drive arrangement includes a drive shaft which is releasably connected through a universal joint to the neck of a roll. An inner shaft and an outer shaft connected with the inner shaft are mounted so as to be axially displaceable. For coupling the neck of the rolling mill roll with and for uncoupling the neck of the roll from the corresponding yoke of the universal joint of the drive shaft, a positioning unit is provided which acts on the inner shaft and the outer shaft and which includes a pressure medium cylinder fastened to the outer shaft and a piston rod mounted on the inner shaft. For actuating the pressure medium cylinder, the outer shaft is moved onto the inner shaft and, thus, the shaft is shortened until the coupling yoke of the universal joint is pulled off the roll neck. This known arrangement for pulling off rolls is of complicated construction. The drive shaft is constructed in two pieces. Also, a separate device is required for fixing the shaft after the uncoupling from the roll. A separate device consists of spring arrangements, support rods, etc. which make it difficult to quickly and precisely couple an uncouple the drive shaft and the rolling mill row.
It is, therefore, the primary object of the present invention to improve the rolling mill drive of the above-described type by means of a simple, compact and very accurately adjustable structural arrangement, so that the replacement of the work rolls and the separation of the work roll and the spindle is made simpler and can be carried out more quickly than in the past. Particularly high requirements are to be met with respect to the precision of the exchange in order to reduce the loads acting on the roll bearing and the spindle joint during the roll exchange as much a possible.